By hannah h



Aug. 24 1926. Re. 16,407

' H. H. FREY LBVBL IIIDIGATING APPARATUS 0111M]. Filed llay 10, 191B;

drwenbr flQIbQIZ J-l. Jrgq by Hannah/i 512g,

b ham? M Reiaued Aug. 24, 1926.

UNITED STATES PATENT OFFICE.

ADIINIB'IBATBIX, OI CHICAGO, ILLINOIS, ASSIGNOB, BY KES NE ASSIGNMENTS, TO STBOKBEBG MOTOR DEVICES COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OI- ILLINOIS.

Original application fled Kay 10, 1918. Serial 1T0. 288.748. Renewed September 2, 1921, Serial No.

8,008. Original No. 1,398,805, dated December 6, 1921.

use. lerlal No. 878,778.

'My invention relates to level indicating apparatus.

It is often desirable to give an indication of the level'of liquid in a tank, at a con 5 siderable distance from the tank.

Heretofore mechanical indicating means, including floats, have generally been employed. I find that suchdevicesare unsatlsfactory, particularly where the vessel in which said float apparatus is contained is subjected to motion or vibration. There is furthermore a practical limit to'which said indications can be transmitted mechanical- 1y. My resent invention aims to provide an improv indicating devicefor giving an indication of the-height of the liquid in a vessel, closed or open, located at any desired distance from the indicating element and positioned at an desired level with respect to the indicating element. all without the use of mechanical connecting or indicating means.

Specifically the ap aratus which I provide 0 rates upon well iinown pneumatic principles and particularly is used upon the ex riments of Pascal and Torricelli.

provideavessel having an 0 en bottom like a divin bell, which vessel 1s adapt ed to be partia ly submerged in the li uid in the tank, depending upon the love of the liquid in the tank. This vessel or hell traps air or gas between its closed top and the surface of the liquid. The air or gas is thus placed under a pressure equal to the pressure of a column of liquid of the height to which the vessel is submerged. The air or gas is subjected to the s'ubmer nce pressure existing at the mouth of t e vessel.

I provide a special form of manomel er of my own invention to form the indicating element for indicating the submergence pressure within the vessel or hell. This manometer is connected to the vessel or hell through a tube of small bore so that the submergence to give an indication of the submergence pressure. and consequently of the level in the tank. The height of the liquid'column in pressure is transmitted to the manometer LavnL-mmcarme arramrns.

Application for reissue filed December 5,

'1' H. rant, DECEASED, LATE OF CHICAGO, ILLINOIS; BY H. IBEY,

the manometer balances the height of the A liquid above the level in the vessel or bell.

The manometer is constructed of a. U-tube in which the one leg of the U is formed in the shape of an enlargement or chamber. This leg 1 term the storage leg. T he other, or indicating leg comprises a tube of small bore. The storage l e is of a relatively great capacity compare to the indicating leg, so that only small variations in level willbe occasioned by full scale variations in the indicating leg. This relation of sizes of the indicating leg and the storage leg is of importance in recharging the pressure system to be mentioned later.

I have found that due to various causes such as absorption of the air or other gas in the vessel or hell, leakage of the air or gas out of the pressuresystem and the like, there is a tendency for the air or gas in the pressure system to become reduced, giving an erroneous indication.

This reduction in the amount of air or other gas in the pressure system may be corrected in a number of ways without deranging the manometer or other parts. It is inadvisable to inject the air or other gas for recharging the pressure system directly into the pressure conduit for a number of reasons. One reason is the necessity for introducing valves or other connections which are apt to leak. Another reason is the danger of blowing the indicating liquid out of the manometer without a suitable three way or check valve arrangement.

I provide means for introducing the gas into the pressure system through one of the liquids or by raising the vessel or hell out of the liquid in the tank to dpermit the vassci or bell to be recharge from the atmosphere.

I have. found that where the indicator is located at some distance from the tank the best form of apparatus for effecting the recharging of the pressure system is a pipe connected to the open end of the indicating leg of the manometer, which i is connected with a suitable source 0 air or other gas under pressure. To recharge the sys tem the air or other gas is forced through the indicating leg of the manometer, driving the indicating liquid into the stora e chamher in the storage 1 and then bub ling up through the indicating liquid and assing into the pressure system. The in icating liquid in the manometer thus serves the function of a valve for admitting and trapping the air or other gas into the pressure system. Any excess of air or other gas isblown out of the bottom of the vessel or hell. The relation of sizes between the indicating leg and the storage leg of the manometer occasions only very slight changes inlevel in the storage leg when the liquid from the indicatin leg is forced into the storage leg for recharging the pressure system, which therefore entails the production of negligible negative pressure.

Instead of introducing the air or other as through the indicating liquid, I have ound that it is equally feasible to introduce the same through the liquid in the tank b placing a pipe in the liquid of the tan with the open end of the pipe located below the opening in the vessel or bell, so that upon blowing air or other gas through this pipe it will permit the air or other gas to pass up through the liquid and through the opening in the bottom of the vessel or hell to recharge the pressure system. \Vhen the pressure of air or other gas is cut oif from such pipe the liquid in'the tankflows into the open end of the pipe and thus forms a trap or valve effectively preventing the es cape of ressure from the pressure system. The emp oyment of the liquid as a trap for sealing the pressure system is the same in either case.

'lVhere my device is employed for measuring the variations in ii uid in thenature of gasoline or such oils, find it advisable to employ an indicating 1i uid of less density than mercury, but of su stantially great-' or density than water, alcohol or the like. 1 have found that in most commercial installations it is advisable to have the indicator of relatively smaller size than the tank, and inasmuch asthe tank for holdin gasolene and the like on automobiles and other commercial vehicles is limited to about 12 to 15 inches, and whereas the indicator must be limited to substantially 6 inches for suitable location on the dash board of the vehicle, I provide a liquid of a specific gravity in the neighborhood of 2 to 4.

This permits of a satisfactory and workable arrangement for givin the maximum indication within the limits imposed by' fixed conditions.

Another valuable feature which 'I have provided is the employment of a small bore tube connecting the indicating leg with the storage leg so that inequalities in the level 'of the liquid in the tank caused by motion of the vehicle or the like, will not make themselves immediately apparent on the indicating leg.

This reduction in the size of the tube connecting the two legs has a double function. It serves first as a restriction for the, flow of liquid during riseand fall in the indicating tube and to reduce the volume of liquid lying between the indicating leg proper and the storage leg. As a'further improvement I have placed the vessel or bell a fixed distance above the outlet of the tank in order to maintain a reserve sufiicient to permit the vehicle to proceed some distance after giving an indication that the tank is empty with respect to normal conditions.

This location of the vessel or bell above the bottom of the tank has a further important function of permitting automatic recharging of the pressure system as will be described in detail later.

I contemplate the use'of a liquid seal or check valve for recharging the storage system whether the liquid so employed be used for the indicating liquid or not. For instance I may employ a pressure gage for indicating level and may then employ a liquid sealed inlet for recharging the pressure system. Mercury may be employed for thus sealing the system, a small column only being required.

In order to acquaint those skilled in the art with the manner in which my invention may be constructed and practised, I shall now describe in detail one embodiment of my invention in connection with the accompanying drawings, which form a part of the specification.

The single figure of the drawing indicates diagrammatically one embodiment of my invention. A containing tank 1 for containing a. body of liquid such as fuel is provided with an outlet 3, preferably in the form of a valved pipe or the like and an inlet or filling opening 4. The tank may be either closed or open. Within the tank 1 I provide a vessel orbell 5 having an open ottom 6. The vessel or bell 5 is connected to a tube 7 of small diameter which passes out of the tank as for example through the top 8 of the containing tank 1 and leads to the manometer 10 which is located at any desired distance from the containing tank 1. The manometer may be placed at any desired level with respect to the tank.

The manometer 10 comprises a U-shaped vessel preferably made in whole or in part of glass. The one leg of the U indicated at 11 is formed with an enlargement or chamber to form a receiving or storage chamber for the indicating liquid 12. The other leg 13, which I term the indicating leg of the manometer, consists of a tube of small diameter, the cross section of the tube or leg 13 being relatively much smaller than the cross section of the leg 11. This proportioning of the two legs of the manometer serves a double function. First of all, the relative sizes permits the indicating liquid 12 to rise in the indicating leg 13 without appreciably lowering the level of liquid in the storage leg 11 so that the height of the column in the leg 13 above zero may be taken as an indication of the level in the tank. A further par of the enlargement in the storage leg is to permit the recharging of the pressure system without expelling the li aid 12 from the manometer, or occasiouing ny app reciable rise in the liquid in the storage leg.

or this latter purpose I have provided a flexible tube 14 which is connected to the upper end of the indicating leg 13 and is prO- v1 ed with a mouth piece 15 so that the user of the ap aratus may blow through the tube 14 to rec urge the pressure system. Any other means or source of pressure may be employed.

I provide a scale 16 which is so placed with respect to the indicatin leg 13 that by comparison of the height the column of liquid as indicated at a 1n the figure, with the corresponding aduations on the scale 16, the observer is a le to ascertain the height of the li uid in the tank 1.

nasmuch as there is a well defined practical limit of the depth of the ordinary automobile fuel tank, and inasmuch as it is desirable to have the scale 16 of a convenientl small height but at all times large enoug to indicate plainly the difierences 1n level, I find it necessary to provide a special liquid for use in this connection. Inasmuch as the entire indicati instrument should not exceed 6 or 7 inc es, so as to be conveniently placeable on the dashboard of the vehicle, I provide a liquid of a specific gravity of the a order of 2 to 4. Such liquid may be a m1x ture of mercury iodid and potassium iodid.

When the vehicle is in motion the level of the liquid may vary, due to such motion and due to surging back and forth, so that pulsations of pressure in the pressure system might tend to cause similar pulsations in pressure on top of the liquid in the storage e 11' and thus cause uctuations of the co umn of liquid in the indicating leg 13. To prevent such sharp changes or minor fluctuations in level being immediately transmitted to the indicating column, I provide a. restricted channel between the storage leg and the indicating leg in the shape of a small bore tube as shown at 17. The tube 17 permits only of slow variations in level being indicated and tends to damp out any surging or oscillation.

The pressure system comprising the top of the storage leg, the conduit 7 and the vessel or hell 5 may extend to any convenient distance or height within limits, but it should be fluid tight. In case of leakage of the fluid within the pressure system, an erroneous in dication on the manometer would be given.

Similarly if the fluid within the pressure system were absorbed by the liquid in the tank, or by the indicating liquid in the manometer. an erroneous indication might be iven. I have provided means for recharging the pressure system automatically by piecing the bottom of the vessel or bell a predetermined distance above'the' bottom of the tank 1. This serves a double function. The manometer indicates for a full scale division, as indicated by h on the scale 16 the height H of liquid above the bottom of the vessel or bell 5 in the tank 1. As the liquid 2 is drawn olf through the connection 3, the level will drop below the mouth of the vessel or bell 5, thereby, permitting this vessel and the pressure system to become recharged with air at atmospheric pressure. At the same time the indicator will indicate that the tank is at zero level. However, when the indicator ives an indication of zero level in the tank, tliere is still a reserve supply in the bottom of the tank which will suffice for driving the vehicle a considerable distance. Consequently the pressure system will be automatically recharged just before the tank is filled, so that a correct indication of the de cc of filling of the tank will be given.

' g have provided further means for permitting the pressure system to be charged by forming the conduit 7 so that the vessel or boll 5 may be drawn above the level of the liquid in the tank 1 to permit the system to become recharged with air at atmospheric pressure. When the bell is again submerged to the proper extent the indicator will give the correct indication of the heightof the liquid level in the tank. To permit the vessci or bell 5 to be raised I have shown a coil or flexible portion 18 in the drawing.

The operation of the device is as follows. Normally when the tank 1 is empty or contains liquid the level of which lies below the mouth of the bell or vessel 5 the pressure system contains air at atmospheric pressure. The indicating liquid 12 will stand at the same level in both of the legs 11 and 13. When the tank is further filled with liquid so that the air is trapped in the vessel or bell 5, such air will be subjected to the submergence pressure of the mouth of the vessel or hell and this pressure is transmitted through the conduit 7 to the storage leg of the manometer 10. The pressure exerted upon the top surface of the liquid 19 in the storage .leg 11 causes the column of liquid to rise in the indicating leg to such a height It is to be noted that the tube forming the indicating leg 13 should not be a capillary 1 as to balance the pressure in the storage leg.

' tube, otherwise there would be a tendency Q uids, and account would have to be taken of i for the capillary action to interfere with the balancing of pressure.

It is further desirable to have the leg 13 of a diameter of a size greater than capillary dimensions in order to give good vlsibility of the column of li uid.

In case the system has een standing for some time so that some of the air might have leaked out of the pressure system or some of the air might have been absorbed by the liquid 2 in the tank 1, the 0 erator may recharge the system either by raining the tank 3 to a point below the opening in the bell 5 or b raising the bell 5 above the level 0 the liquid 2 or b blowing air through either the liqui 12 or the liquid 2 into the system. Where the indicator is at some distance from the tank 1 it is more convenientto supply the air or other gas by forcing'the same through the manometer, the liquid of which is thereby driven into the storage leg to form a liquid check or seal between the pressure system and the atmosphere I Where air is employed in the pressure system the operator may simply blow through the tube 14 and the tube13, driving air through the liquid into the pressure system, any excess of air being discharg d from the mouth of the vessel or hell 5 in the tank 1. As previously indicated a tube may be laced in the liquid 2 with its'opening'beow the opening 6 of the tank 5 and air may be blown through saidtube, the same rising into the vessel or hell 5 and thus replenishing the pressure system. 7

It is not essential that air be em loyed in the pressure system. Any suitable uid ma be emplo ed under the proper conditions. t is advisable to em loy air or some other gas which. is relativei; neutral to the liquids 2 and 12. If a liquid be employed in the pressure system, suitable istons or diaphragms would be required etween the liquid in the pressure system and the other liqthe difference in level of the various parts of the pressure system. a

e liquid position.

I do not intend to be limited to the precise details of construction shown and described.

I claim 1. In combination, a tank for liquid, a chamber having an opening at its lower end 12 may be of any suitable comcommunicating with the liquid in the tank and providing an airspace at its upper end, a manometer comprising a U-tube, one leg of said U-tube being'of substantially greater diameter than the other, a pressure conduit for gas connecting the air space of the chamber and the upper part of said enlarged leg of the U-tube, and a liquid forming a trap in conduit by creating an excess of gas pressure on the indicating leg and forcing the liquid and air through the restricted bore into the enlarged leg of the U-tube.

2. In combination, a tank for liquid of specific gravity less than unity, a chamber having an opening at its lower end communicating with the liquid of the tank, a conduit communicating with the interior of the chamber, said conduit having a trap in the form of a U-shaped bend therein and liquid of a s ecific gravity of substantially 2 lying in sai trap, said trap having indicating means for indicating in terms of quantity or level in the tank and means through which gas maybe forced through said U- shaped bend into the conduit.

3. In combination, a tank for liquid, a

chamber having an opening at its lower end communicating with the liquid in the tank,

a manometer having a small indicating leg and a large storage le the storage leg having connection to sai' chamber, a pressure indicating liquid of a specific gravity greater than unity in said manometer, the manometer having a restricted bore connecting the two legs which prevents any but relatively slow changes of level of the liquid in the.indicating leg due to changes of level of :liguid in said chamber and means for causing gas to pass through the restricted portion and up through the liquid in the storage leg.

t. In combination, a tank for liquid,'a chamber having an opening communicating with the liquid of the tank, a conduit communicating at one end with the top of the chamber, an indicating manometer connected to the opposite end of the conduit, and means for introducing a suitable gas into the conduit, by causing gas to pass through both legs of the manometer.

5. The improvements herein described, comprising a tank for liquid, a chamber communicating at its lower end with the li uid in the tank, a manometer tube having alarge storage leg and a small indicating leg, a liquid seal in the manometer tube, a pressure conduit connectingthe chamber and the stora e leg of the manometer, means the liquid in the storage leg into the pressure conduit. .7

6. A liquid level indicator adapted to in- 'dicate the depth of liquid in a container including a closed chamber partially filled with an indicating liquid,

one end adapted to extend into the liqu in the container at the full depth to bemeasured and having the other end openin into said chamber above the indicating iquid therein, a gage tube open at its upper end and in communication at its lower end-with said chamber below the level of indicating liquid therein whereby said liquid will rise in said gage in proportion to the depth of liquid in said container, and means whereby atmospheric air is caused to ass through the gage tube, indicating liqui and chamler to replace any absorbed air in the conuit.

7. An apparatus for indicating the depth of li uid in a container comprising a closed cham er partially filled with an indicating liquid, means forming a confined air column between the air space in the chamber and the liquid in the container at the full depth to be measured, a gage tube, means establishing communication between the lower end of the gage tube and the chamber below the level of the indicating liquid therein, means establishing communicationbetween the upper end of the gage tube and a source of air pressure whereby, upon applyingsaid pressure, atmospheric air may be forced through the gage tube, indicating liquid and chamber into the confined'air column.

8. In a device of the class described, a tankv containing liquid the depth of which is to be indicated, a bell submerged in said liquid and having a terminal opening which is sealed by the liquid, said opening forming one terminal of the system hereinafter defined, a, U tube manometer, one 1c of which comprises an indicating leg an has a terminal opening leading to atmosphere and forming another terminal .of the system, a liquid in said manometer forming a seal to prevent the escape of air from' the latter'terminal, a tube connecting the other leg of the manometer with the top of the bell to form with said bell and manometer a closed air tight' system for confining a body of air between the liquid sealsat said terminals, and means at one of said terminals having series connection with the system and through which air may be forced into the terminal opening and through the liquid seal of said one terminal to inject air into the system.

9. In a fuel indicator for automobiles, the combination of a tank for liquid fuel, an in- 'dicating device therefor comprising a conduit for air, the lower end of which is ena conduit having larged to form an air chamber having its lower end submerged in the liquid fuel at substantially the full dc th .to be measured, and a pressure actuate indicating device graduated in terms of liquid in the tank connected to the upper end of said conduit, said device comprising a fluid flow restriction for damping out oscillations of the indicator caused by sharp variations of pressuresuch as occur in the air chamber upon sharp variations in level of liquid in said tank.

10. A liquid level indicator adapted to indicate the depth of liquid in a container, comprising a continuous conduit opened at each end, the upper end opening into the atmosphere and the lower end opening into the liquid at substantially the full depth to be measured, the conduit adjacent its'upper end comprising a U-shaped portion, containing an indicating liquid, and forming a, manometer, means whereby air is caused to pass through the manometer into the part of the conduit between the indicating liquid and the liquid in the container, to replace any absorbed air in the conduit, said conduit having a flow restriction limiting the rate of entry of air through the manometer, to prevent the liquid from being driven out of the manometer.

11. A liquid level indicator adapted to indicate the depth of liquid in a container, comprising a continuous conduit opened at each end, the upper end opening into the atmosphere and the lower end opening into the liquid at substantially the full depth to be measured the conduit adjacent its upper end comprising a U-shaped portion, containing an indicating liquid, and forming a manometer, means whereby air is caused to pass through the manometer into the part of the con uit between the indicating liquid and the liquid in the container, to replace any absorbed air in the conduit, said conduit having a flow restriction limiting the rate of entry of air throughthe manometer, said restriction bein disposed in a part of the manometer whic is normally occupied by liquid and serving also 'to damp oscillations of the indicating liquid due to sudden variations in level of liquid in the container.

In witness whereof, I hereunto subscribe my name this 3rd day of December, A. D., 1923.

' HERBERT H. FREY, By HANNAH H. FREY, Administrat'riw of the estate of Herbert H.

Frey, deceased. 

